1. Field of the Invention
This present invention relates to a turbo-charcoal barbecue, and is more particularly concerned with an adjustable charcoal tray, a fire screen for spreading the heat from the charcoal tray, an adjustable rotisserie, and an air circulation unit for recirculating hot air between the charcoal tray and the grill.
2. Description of the Related Art
The cooking of food items by the application of heated smoke from a burning fire fueled by wood has been practiced for many years. Grilling foods upon an open surface over charcoal briquets gives food a unique flavor and appearance by grilling portions of the food in contact with the grill. The art of grilling food involves a complex carmelization process which depends on many factors including length of time and intensity of applied heat.
Many earlier patents use heat transfer through radiation together with convection heating from the circulating air and conduction heating through the grill's surface in hopes to perfect the carmelization process. The achievement of uniformly cooked meat and the efficient use of fuel and energy are some continual problems associated with the operation of barbecues. Most conventional grills do not adequately allow the user a means for regulating the intensity of heat needed to properly grill foods. Reducing the temperature of the heat source can diminish the effect of radiation heat transfer and leave the user with only relatively inefficient convection heating to grill the food.
Air blowers and plenum chambers have been used in the past to force air passed a heat source to improve heat transfer efficiency, however, after the air is forced past the food product it is exhausted and no longer redistributed within the barbecue to aid in grilling process. Some barbecues described in earlier patents such as U.S. Pat. No. 4,823,684, issued to Traegar, et al. on Apr. 25, 1989 and U.S. Pat. No. 3,933,145, issued to Harry Reich on Jan. 20, 1976 are designed to direct air circulation directly through ignited briquets.
U.S. Pat. No. 5,154,159, issued to Knafelc, et al. on Oct. 13, 1992 describes a bowl shaped barbecue cooker that incorporates a briquet ignition and air blower system designed specifically to quickly and evenly ignite briquets as well as produce an even distribution of hot air across the surface of the char grill. The char grill is made of a set of upper concentric rings spanned by a plurality of parallel rods. The ignition chamber has a cylindrical shaped wall and is perforated with holes. The ignition chamber communicates with an air blower by means of perforated plenum chamber wall which distributes combustion enhancing air evenly to the surfaces of colder briquets for rapid heating.
A cranking mechanism is provided for raising heated briquets from an ignition chamber onto a char grill. The mechanism includes a housing which is unitary with a sleeve which is, in turn, rotatably mounted by extended flanges within the base cylinder. The crank and handwheel mechanism includes a conventional brake or locking device. Manipulation of the crank and wheel mechanism winds a cable around the handwheel and causes the elevator shaft and elevator platform to rise.
This prior art patent only uses its air blower system to rapidly ignite briquets. A major problem with this circulation process is that hot ashes may be distributed throughout the enclosure of the barbecue and fall onto the food being grilled. When the air blowing process has been completed, the blower system shuts down and does not have any other use. A large percentage of heat produced by the briquets is expelled below the charcoal tray which holds the briquets. Therefore, it would be desirable to have a continual circulation process designed to recirculate air from under the ignited briquets and redistribute that air to the char grill.
A further problem that relates to the crank and handwheel mechanism is it utilizes a cable. A common problem associated with most cables is the constant wear which causes breakage. Also, there are time and cost considerations concerned with replacing broken cables. A cableless crank which raises and lowers a charcoal platform to increase or decrease heat intensity would be a preferable mechanism.
U.S. Pat. No. 5,000,085, issued to Virgil Archer on Mar. 19, 1991 describes an air slot cooking device which recirculates its hot air for grilling foods. The air slot cooking device is formed from an enclosure having a bottom, side walls and a removable top. A housing abuts a side wall of the enclosure. The housing communicates fluidly with a chamber through an air flow opening. Located within the housing chamber is a blower which recirculates air throughout the enclosure.
A grill that supports food extends to all side walls of the enclosure and divides the enclosure into an operating space above the grill and a heat supplying space below the grill. A heat supplying element is mounted in the heat supplying space and above the base of the base of the enclosure. A jet curtain plate containing various slot widths is mounted in the heat supplying space of the enclosure and spaced apart and above the heat supplying element. The slots are designed to yield streams of air having different velocities at different areas of the jet curtain plate, this provides certain areas of the grill to have various cooking speeds.
After the hot air strikes and heats the food product on the grill member, the air then flows rearwardly and downwardly into the base housing return plenum. From the return plenum, the heated air is drawn into a fan impeller disposed within the base housing discharge passage. The air is drawn horizontally into the heating plenum where it traverses and absorbs heat from the heating element. To complete its recirculating path, the heated air is then directed to air slot openings in the jet curtain plate and redirected back to the grill. Although this patent recirculates hot air within the enclosure of the barbecue, it is only adapted for a heating element and not for charcoal. The advantage of briquets over other heat sources such as gas and electrically powered barbecues is that briquets create a smoke similar to wood-based fires which is needed to produce a certain flavor to cooked food.
U.S. Pat. No. 4,773,319, issued to Robert Holland on Sep. 27, 1988 describes a barbecue having a bottom surface, a heat source adjacent the bottom surface, a heat deflecting means positioned above the heat source, a grease collection and drainage system, a food supporting grill, and a hood for enclosing the housing. The heat deflector acts as a grease collector, operates to distribute heat to obviate "hot spots," and blocks undesirable flaming which causes overburning. The heat deflector/grease collector is designed with inward sloping sides that connect to form a channel for directing grease spills. Although the heat deflector plate blocks unwanted flames from directly burning the food product on the grill, the plate creates an uneven flow of heat applied to the grill.
The heat deflector plates redirects a vast amount of the heat flow around the edges of the heat plate and to the outer edges of the grill. This air flow intensifies the heat energy to the outer edges of the grill instead of an even distribution of heat over the entire grill surface. An ideal heat deflector apparatus would not only block flames directed to the grill, but allow the heat to flow through the plate and be evenly applied to the entire grill surface. Previous patents such as U.S. Pat. No. 4,800,865, issued to Michael Setzer on Jan. 31, 1989, U.S. Pat. No. 4,658,710, issued to Hector Quet on Apr. 21, 1987, U.S. Pat. No. 4,418,615, issued to Michael Higgins on Dec. 6, 1983, and U.S. Pat. No. 4,209,006, issued to Stephen Marsalko on Jun. 24, 1980 do not recirculate its hot air because heat escapes through chimneys mounted in the barbecue's hood.
U.S. Pat. No. 2,968,301, issued to Robert Cowart on Jan. 17, 1961 is a barbecue having a front wall, a back wall, and side walls. The front wall is provided with an opening into an oven chamber in the cabinet and a door opening into fire pit chambers. A grill is situated in the interior of the cabinet between the oven and the fire pit chambers. The barbecue also has an adjustable fire lift secured by a vertical adjustable fire pin designed for raising and lowering a fire pan. The fire lift affords a means for lowering the fire pan beneath the grill whereby any flames arising from the fat drippings will not damage the food product being cooked. Although this fire lift system is cableless, this prior art was designed for industrial sized fire pits. The lift system described in this prior art may operate too slow in lowering the lift because fat drippings rapidly fuel flames that quickly strike upwards towards the grill and may cause food to be burnt. An ideal barbecue would not burn food products on its grill.
A barbecue should contain a design feature that recirculates hot air within its enclosure to conserve fuel and energy. A fire screen should be included to allow an even distribution of heat to the entire grill surface and deflects uncontrollable flames fueled by fat drippings. An apparatus that would allow the barbecuer to monitor the temperature inside the barbecue at all times and a device that operates to exhaust hot air when the temperatures inside the enclosure is to high.
None of the above inventions and patents, taken either singularly or in combination, is seen to describe the instant invention as claimed. Thus a turbo-charcoal barbecue solving the aforementioned problems is desired.